Antibiotic resistance is a major health problem. In part this is attributed to the widespread use of antibiotics not only in medicine, but in agriculture and animal husbandry. Such overuse, while killing susceptible organisms, has also created a powerful selection bias toward antibiotic resistant bacteria. The resulting strains pose a particular problem for individuals with weakened immune systems. In addition, they represent an increasingly serious problem for patients in hospitals.
In addition to exhibiting inherited antibiotic resistance, many emerging bacterial strains can exist in complex associations known as biofilm. The structure of the biofilm constitutes a physical barrier to antibiotic exposure. Biofilms can form in and on tissues, particularly on chronic wounds and medical implants, such as indwelling catheters, artificial organs, and the like, where they have the potential to cause systemic infections requiring heroic treatments. There is an urgent need for materials that are active against antibiotic resistant organisms in both free and biofilm form.
As part of their natural defense against bacteria, many organisms, including insects, amphibians, mammals, and humans, produce antimicrobial peptides. Such peptides are chemically diverse. Some appear to act by penetrating the bacterial cell membrane and destroying it. Others affect bacterial cellular processes. Considerable selectivity is observed, with many of the peptides targeting bacteria in preference to host cells. Unfortunately, host produced antimicrobial peptides are not capable of effectively eliminating a wide range of microbial agents, including many antibiotic resistant bacterial strains. Antimicrobial peptides capable of augmenting the host's antimicrobial defenses are therefore desirable.